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netarch
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Fix two bugs in TCP resequencer, but I'm not done yet

This commit is contained in:
Neale Pickett 2009-04-06 15:08:25 -06:00
parent 41a3eae8ab
commit 90d3a08a36
1 changed files with 15 additions and 16 deletions
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31
ip.py
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@ -240,11 +240,6 @@ class TCP_Resequence:
# Does this ACK after the last output sequence number? # Does this ACK after the last output sequence number?
seq = self.lastack[idx] seq = self.lastack[idx]
if pkt.ack > seq: if pkt.ack > seq:
if self.closed[idx]:
# XXX: If the next thing happens, that means you need to
# return a gapstring to deal with dropped frames
assert (pkt.ack == seq + 1)
return
pending = self.pending[xdi] pending = self.pending[xdi]
# Get a sorted list of sequence numbers # Get a sorted list of sequence numbers
keys = pending.keys() keys = pending.keys()
@ -261,22 +256,27 @@ class TCP_Resequence:
# Fill in gs with our frames # Fill in gs with our frames
for key in keys: for key in keys:
if key >= pkt.ack: if key >= pkt.ack:
# In the future
break break
if key < seq:
# Hopefully just a retransmit...
del pending[key]
continue
elif key == seq: elif key == seq:
# Default # Default
pass
elif key > seq:
# Dropped frame(s)
gs.append(key - seq)
seq = key
frame = pending[key] frame = pending[key]
gs.append(frame.payload) gs.append(frame.payload)
seq += len(frame.payload) seq += len(frame.payload)
del pending[key] del pending[key]
elif key < seq:
# Hopefully just a retransmit. Anyway we've already
# claimed to have data (or a drop) for this packet.
del pending[key]
continue
elif key > seq:
# Dropped frame(s)
gs.append(key - seq)
seq = key
print (seq, pkt.ack, self.closed[idx], self.closed[xdi])
if self.closed[idx]:
# FIN increments the sequence number
seq += 1
if seq != pkt.ack: if seq != pkt.ack:
# Drop at the end # Drop at the end
gs.append(pkt.ack - seq) gs.append(pkt.ack - seq)
@ -289,7 +289,7 @@ class TCP_Resequence:
# Is it a FIN or RST? # Is it a FIN or RST?
if pkt.flags & (FIN | RST): if pkt.flags & (FIN | RST):
self.closed[idx] = True self.closed[idx] = True
if self.closed == 3: if self.closed == [True, True]:
# Warn about any unhandled packets # Warn about any unhandled packets
if self.pending[0] or self.pending[1]: if self.pending[0] or self.pending[1]:
warnings.warn('Dropping unhandled frames after shutdown' % pkt) warnings.warn('Dropping unhandled frames after shutdown' % pkt)
@ -555,7 +555,6 @@ class Session:
""" """
print 'Lastpos: %s:::%d' % self.lastpos
packet.show() packet.show()
def done(self): def done(self):